New Medical Device and Irrigation Solution Exhibits Promising Results in the Removal of Bacterial Colonization in Chronic Sinus Infections

MINNEAPOLIS, Nov 29, 2007 (BUSINESS WIRE) -- MDT | charts | news | PowerRating -- Results of a laboratory study published in the November issue of the American Journal of Rhinology suggest that pressurized irrigation of the sinuses in conjunction with a specially designed irrigation solution may offer new options to reduce bacteria associated with chronic rhinosinusitis (CRS).

"Methods for Removing Bacterial Biofilms: In Vitro Study Using Clinical CRS Specimens," led by Martin Desrosiers, M.D., associate clinical professor in the Department of Otolaryngology and Allergy at Montreal General Hospital, McGill University in Montreal, Canada, showed a large reduction of very robust and highly adherent bacterial colonies in a laboratory model. Two strains of bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, were clinically isolated from CRS patients who had poor outcomes following functional endoscopic sinus surgery. Authors of the study, which was presented at the spring meeting of the American Rhinologic Society held last April in San Diego, Calif., received the ARS Basic Science Research Award.

The bacterial strains were grown into robust bacterial colonies and treated with a variety of commonly used therapies including antibiotics and hypertonic saline. These existing therapies were compared to static and pressurized application of a new irrigation solution under development at Medtronic (NYSE:MDT). Of the S aureus and Pseudomonas bacterial colonies grown in this model, respectively 99.98% and 99.999% of the bacteria were removed by the pressurized application.

Study Results Suggest Improved Efficacy in Bacterial Removal

Researchers at McGill University in Montreal, Montana State and at Medtronic collaborated to test the effectiveness of pressurized irrigation with the citric acid zwitterionic surfactant irrigating solution.

Bacteria isolated from failed surgical patients at McGill were sent to Montana State, grown into robust bacterial colonies, and treated with a number of static and dynamic irrigation solutions. Commonly used controls were compared to static and pressurized applications of the Medtronic surfactant. Control groups included many of the currently used irrigation solutions, containing antibiotics (tobramycin and doxycycline), and salt water (isotonic and hypertonic saline).

When applied statically, none of the controls had any material effect on the bacterial colony. Conversely, dynamic application of saline reduced the number of bacteria by 99.4% in both types of bacterial colonies. Static application of the surfactant reduced the number of bacteria in the colonies of S aureus and Pseudomonas 99.66% and 99.87% respectively. The best results were achieved when surfactant was applied under pressure, where 99.98% and 99.999% of S aureus and Pseudomonas were removed equaling a four- (10,000x) and five- (100,000x) log reduction, respectively.

"Given the positive results of this laboratory study, we are initiating a number of studies to further evaluate this technology," said Bo Lewis, senior director of marketing for the ENT business at Medtronic. "Recent studies suggest that bacteria are much bigger players in the inflammation associated chronic sinusitis and chronic otitis media. We're optimistic that, when commercialized, we will be able to improve the removal of bacteria during sinus surgery and ventilation tube surgery."

Several living tissue and safety studies are scheduled to start in the near future with subsequent submission for review by the FDA.

About the ENT Business at Medtronic

Located in Jacksonville, Florida, the ENT business at Medtronic develops and manufactures products designed to treat ear, nose and throat (ENT) diseases. As the market leader in ENT, Medtronic is changing the way ENT surgery is performed with innovative, minimally invasive products and techniques that benefit both patients and surgeons. Main products include powered tissue-removal systems and other microendoscopy instruments, nerve monitoring systems, disposable fluid control products, image-guided surgery systems and a Meniere's disease therapy device. Learn more about the ENT business on the web at www.MedtronicENT.com

About Medtronic

Medtronic, Inc. (www.medtronic.com), headquartered in Minneapolis, is the global leader in medical technology - alleviating pain, restoring health, and extending life for millions of people around the world.

Any forward-looking statements are subject to risks and uncertainties such as those described in Medtronic's Annual Report on Form 10-K for the year ended April 27, 2007. Actual results may differ materially from anticipated results.

SOURCE: Medtronic, Inc.

Medtronic, Inc. Investor Relations: Jeff Warren, 763-505-2696 or Public Relations: Ginny Cassidy, 763-505-2998

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